A team of researchers from the University of Oxford has just announced the results of an experiment carried out at CERN (European Laboratory for Particle Physics, Switzerland) in which it shows the first empirical evidence that a subatomic particle can oscillate between the matter and antimatter. The research, however, has just been submitted to Physical Review Letters and is awaiting the peer review process, although it is available as a preprint in the arXiv repository.
Charm mesons are a type of boson containing a quark and an antiquark, and their ability to travel with a mixture of their particle-antiparticle states has long been known. However, these new results show that these atomic particles can spontaneously oscillate between the two states. This new scientific evidence will allow scientists to address some of the most important questions in physics about particle behavior that cannot be explained by the standard model, which is the most robust theory in physics so far.
Matter and antimatter
As we have already commented, charm mesons can be particle and antiparticle at the same time, in a phenomenon known as quantum superposition, which results in two particles, but each one has its own mass. The existence of the two versions, heavy and light, allow the meson to oscillate from the particle state to the antiparticle state and vice versa.
Using data collected during the second run of the Large Hadron Collider (LHC), the researchers measured a mass difference between the two particles of 0.00000000000000000000000000000000000001 grams, or in scientific notation 1×10-38 g.
It is not the first particle described with this behavior
According to the standard model, there are only four types of particles that can become its antiparticle. This mixing phenomenon was observed for the first time in the 1960s in the so-called ‘strange’ mesons and, later, in 2006, the oscillation of the ‘strange-beauty’ mesons was also demonstrated. “Unlike the ‘beauty’ mesons, the oscillation of the ‘charm’ mesons is very slow and, therefore, extraordinarily difficult to measure,” explains Guy Wilkinson, one of the authors of the new work. “ The oscillations are so slow that the vast majority of the particles disintegrate before they have a chance to oscillate. However, thanks to the capacity of the LHCb we have collected enough data to prove it . “
According to the authors, this discovery of the charm meson oscillation opens up an exciting new phase in the physical examination: the next step is to understand the oscillation process itself, which would be a major step in solving the mystery of matter asymmetry. – antimatter. “Little measurements like this can tell us big things about the Universe that we didn’t expect,” says Mark Williams of the University of Edinburgh. The result, 1×10-38g, crosses the “five sigma” level of statistical significance that is required to claim a breakthrough in particle physics.
